Alberta Lake Management Society Lakewatch 1999 Report
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Alberta Lake Management Society Lakewatch 1999 Report. Preston McEachern G208 BioSci Bldg. University of Alberta, Edmonton, AB T6G 2E9 (780) 492-6304 1 Table of Contents 1. List of Tables. .........................................................................................................................2 2. List of Figures. ........................................................................................................................2 3. Acknowledgements .................................................................................................................2 4. Introduction.............................................................................................................................3 5. Indicators of Lake Water Quality.............................................................................................4 6. Methods ..................................................................................................................................5 7. Results ....................................................................................................................................8 Burnstick Lake ................................................................................................................8 Gull Lake.........................................................................................................................9 Driedmeat Lake .............................................................................................................10 Chestermere Lake..........................................................................................................11 Hastings Lake................................................................................................................12 8. Summary...............................................................................................................................14 9. References.............................................................................................................................15 1. List of Tables Table 1. Average concentrations of major ions, total phosphorus, chlorophyll a and other physical variables in the lakes in 1999 compared to historic data...............................................17 2. List of Figures Fig. 1: Secchi disc depths for Lakewatch lakes 1999 .................................................................18 Fig. 2: Total phosphorus concentrations for Lakewatch lakes 1999............................................19 Fig. 3: Total Kjeldahl nitrogen concentrations for Lakewatch lakes 1999 ..................................20 Fig. 4: Total chlorophyll a concentrations for Lakewatch lakes 1999.........................................21 Appendix 1: Total chlorophyll a and phosphorus concentrations for Alberta Lakes ...................22 3. Acknowledgements The Lakewatch program is made possible through the dedication of its volunteers and Alberta Environment employees. Mike Bilyk, John Willis, Doreen LeClair and Pat Mitchell from Alberta Environment were instrumental in both funding, training people and dealing with lakewatch data. Alberta Lake Management Society members Paula Siwik, Michael Agbeti, Lorelie Marks, Ron Zurawell, Jay White, Craig Taylor and Preston McEachern trained lake volunteers and collected samples. Without the dedication of these people and the interest of cottage owners, Lakewatch would not have occurred. Special thanks to Al Sosiak for providing editorial comments. 2 4. Introduction Alberta’s volunteer lake monitoring program known as Lakewatch has been an important source of water quality data for Alberta Environment and lake associations. In 1999, volunteers from lake associations, the Alberta Lake Management Society (ALMS) and Alberta Environment employees collected water samples bi-monthly from Burnstick Lake, Chestermere Lake, Driedmeat Lake, Gull Lake and Hastings Lake. This report outlines the Lakewatch program and results from the 1999 water quality survey of these five lakes. Why have a volunteer lake monitoring program? Volunteer lake monitoring programs are intended to accomplish four primary objectives for lake management: (i) They act as a platform for educating lake users about the aquatic environment; (ii) they foster and enhance public involvement in lake management; (iii) they facilitate a link between aquatic scientists and lake users; and (iv) they can provide reliable water quality data that, in the present era of funding constraints, can result in cost-saving to government programs. Volunteer monitoring programs have been implemented in several provinces in Canada and states in the U.S., where one or two of these objectives have been emphasized, but usually all four are achieved in part. In Alberta, the volunteer program known as Lakewatch has operated for eight years and collected data from 22 lakes. Volunteer programs elsewhere have become so successful that they have expanded into a principle source for lake quality data. For example, in the United States, the Missouri Volunteer Monitoring Program involves 33 volunteers monitoring 15 lakes annually. The resulting volunteer dataset was independently tested using professionally collected data and was considered highly accurate for its summer mean representation of individual lakes. The utility of volunteer programs in collecting reliable and inexpensive water quality data has been recognized by the EPA to the point that they maintain a web site with access to manuals, data reporting, and data access at http://www.epa.gov/OWOW/monitoring/ How does Lakewatch help Albertans? Much concern has been raised over the ‘pollution’ of Alberta lakes. It is a common belief that human activities, including industry, urbanization, forestry, agriculture, and residential dwellings contribute pollutants to lakes causing excessive algal growth, weeds and murky water. Lakewatch allows people to be involved in determining lake water quality so that they can make informed decisions at council meetings regarding developments that may impact their lakes. 5. Indicators of water quality: Sampling for what? Water samples are collected in Lakewatch to determine basic chemical characteristics that characterize general water quality. Though not all encompassing, the variables collected in Lakewatch are sensitive to human activities in watersheds that can cause degraded water quality. For example, nutrients such as phosphorus and nitrogen are important determinants of a lake's potential productivity. The concentrations of these nutrients in a lake are impacted (typically elevated) by land use changes such as increased 3 agricultural activity or livestock grazing. Increased nutrient concentrations can cause increases in undesirable algae blooms resulting in low dissolved oxygen concentrations, degraded habitat for fish and noxious smells. A large increase in nutrients over time can also warn of sewage inputs resulting in other human health issues such as increases in the protozoan Cryptosporidium. Phosphorus and Nitrogen Phosphorus and nitrogen are important nutrients limiting the growth of algae in Alberta lakes. While nitrogen usually limits agricultural plants, phosphorus is usually in shortest supply in lakes. Even a slight increase of phosphorus in a lake can, given the right conditions, promote algal blooms causing the water to turn green in the summer and impair recreational uses. When pollution containing livestock and human sewage enter lakes not only are the concentrations of phosphorus and nitrogen increased but nitrogen can become a limiting nutrient which is thought to cause blooms of toxic algae. Trophic state is based on phosphorus, nitrogen, and chlorophyll concentrations and is a useful index for rating and comparing lakes. Chlorophyll a Chlorophyll a is a photosynthetic pigment that green plants, including algae, possess enabling them to convert the sun's energy to living material. Chlorophyll a can be easily extracted from algae in the laboratory. Consequently, chlorophyll a is a good estimate of the amount of algae in the water. Chlorophyll a can be used to estimate a lake's fertility or trophic status. Lakes with high levels of chlorophyll a (26 to 75 µg/L) are usually considered fertile and are termed eutrophic. Highly productive or fertile lakes are termed hyper-eutrophic, while moderate to low productive lakes are termed mesotrophic and oligotrophic, respectively. Some highly productive lakes are dominated by larger aquatic plants rather than algae. In these lakes, chlorophyll a and nutrient values taken from water samples do not include productivity from large aquatic plants. The result, in lakes like Chestermere which are dominated by larger plants known as macrophytes, can be a lower trophic state than if macrophytes were included. Unfortunately, the productivity and nutrient cycling contributions of macrophytes are difficult to sample accurately and are therefore not typically included in trophic state indices. Secchi Disk Transparency Lakes that are clear are more attractive for recreation, whereas those that are turbid or murky are considered by lake users to have poor water quality. A measure of the transparency or clarity of the water is performed with a Secchi disk. To measure the clarity of the water, the Secchi disk is lowered down into the water column and the depth where the disk disappears is the Secchi depth. The Secchi depth in lakes with a lot of algal growth will be small while the Secchi depth in lakes with little algal growth can be very